Stability of implants placed in bone reconstructed with block-type interconnected porous hydroxyapatite

Abstract

Artificial bone has been applied to reconstruct bone defects. However, few reports have evaluated implant stability or implant placement after grafting block-type artificial bone. Interconnected porous hydroxyapatite (IP-CHA) has the superior advantage of osteoconduction ability because of porous and interconnected structure. The purpose of this study was to evaluate the stability of implants placed in bone reconstructed with an IP-CHA block. IP-CHA cylinders (D; 6.0 mm, H; 12.0 mm) were grafted into bone sockets in the right femurs of three male dogs. After 3 months, an implant was placed into a socket that was prepared in the central portion of the grafted IP-CHA on the right side, then implants were placed in the sockets (test-group). Simultaneously, an implant was placed into the parent bone of the left femur (control-group). The implant stability quotient (ISQ) was measured immediately after placement. Twelve weeks after implant placement, ISQ and removal torque (RT) measurements were performed to assess implant stabilities. ISQ values in the test-group after 12 weeks were significantly higher than those at the time of placement in the test and control groups (P<0.05). RT was not significantly different between bone sites reconstructed with IP-CHA and parent bone sites. At sites reconstructed with IP-CHA, bone formation was detected around the implant socket. The data indicate that favorable implant stability was achieved at sites reconstructed using an IP-CHA as well as at control. These results showed IP-CHA might be a useful type of artificial bone for preliminary bone reconstruction in implant therapy.